Air-intake heater



y 1930. L. STEARMAN 1,757,488

AIR INTAKE HEATER Filed Sept. 12, 1929 2 Sheets-Sheet l AT oRNEY y 1930. L. STEARMAN 1,757,488

AIR INTAKE HEATER Filed Sept. 12, 1929 2 Sheets-Sheet 2 INVENTOR Patented May 6, 1930, I

UNITED STATES PATEN T OFFICE 1 LLOYD STEARMAN, OF WIGHITA, KANSAS ASSIGNOR TO THE STEARMAN T COMPANY, INC., 015 WICHII'A, KANSAS, A CORPORATION OI KANSAS Ana-INTAKE HEATER Application filed September The objects of this invention are to provide a-simple, ractical and eflicient air intake for aircra engines, which may be used to heat the air or not, as required; which will automatically guard against fire from motor back fire and which, furthermore, will 2'0 respects without departure from the true spirit and broad scope of the invention.

Figure 1 is a broken side elevation and part sectional view illustrating application of the inventionto an airplane. 25 Figure 2 is afront view as taken on substantially the plane of line 2-2'of Figure 1. Fi ure 3 is an enlarged broken plan view illustrating particularly the arrangement of the heater with respect to the exhaust pipes. Figured is a broken sectional view as on substantially the plane of line 4-4 of Flgure 3.

In-Fi gures 1 and 2, the fuselage frame of an airplane is indicated at 5, the cowhngbeing shown by the broken lines 6 and the motor at 7 exhausting into pipes 8 beneath and extending rearwardly at the sides of the body. The carburetor of the motor is indicated generally at 9, located in rear of the motor, within the cowling, and having an air intake at the bottom.

The control and heating of the intake air is effected by an uptake 10, flanged at 11 to mr'ear end of a box or casing 15, carrying on 12, 1929. Serial No. 392,063.

The air passin down the pipes 1 into the top of the distri utor box 15 may be either passed forwardly directly into the carburetor lntake or be forced to pass through the heaters before it reaches the carburetor. This control is accomplished by a damper or swing gate 18, pivoted at 19 in the box or casing 15, with its upper edge operating in the chamber 20 in the to of the casing beneath the entrance of the owntake pipes. This swing valve is shown as controlled by a lever 21 on the protruding end of the pivoting shaft 19, said lever being operated by suitable linkage or control connections taken to a point withm reach of the pilot. 7

With the valve or vane 18in the position shown in full lines in Figures 3 and 4., it will be seen that the air arriving by downtakes 17 will be forced to travel rearwardly in th box 1% and by the transverse conduits 14. to the air heating chambers 13, passing from the forward ends of these chambers through transverse conduits 12 into the forward portion of the box 15, theuptake 10 and so into the carburetor intake. When the vane is swung rearwardly, as indicated in the broken lines, passageto the back is cut off, and the air is sent forwardly directly into the uptake and hence into the carburetor without the preheating last described. Thus, the pilot at will, may preheat or supply theair to the carburetor without reheating. match the air intake in the bottom of the car- To release"back re explosions of the engine and to prevent such explosions from starting fire within the cowhng, an automatic vent and exhaust discharge is' provided in the form of a downwardly directed conduit 22, substantially a downward continuation of the uptake 10, opening outside 2 L'z'rsaees the cowling 6, as indicated in Figures 1 and inechanismin said conduit means for direct- 4, and closed normally by a rearwardly slanting the intaken air to ing trap door" 23 hinged at its forward edge or through the air heater to said engine air at 24 and held normally closed by a spring intake, said conduit means having a back fire 25. -As the suction of the motor is normally discharging vent opening outside the fuseexerted against this trap door, the spring 25 lage and a pressure actuated yielding clomay be relatively weak so as to readily yield sure for said vent.

to the force of a back fire through the muf- 4. In apparatus of the character disclosed, fier intake. Thus, the danger of starting a the combination of engine exhaust pipes 113V: fire within the machine from back firing of ing stoves thereon, a distributor box located the engine, is practically eliminated. between 'said stoves and having transverse The apparatus is relatively small and com conduits at opposite ends" of the same in'conthe engine air intake pact and fits into the ordinarily unoccupied nection with said stoves, saidbox having a space beneath and just to the rear of the part at one endfor connection with the air carburetor. The box portion of the device intake ofan engine carbureter, an air intake 7 is supported by the transverse piping at the conduit opening into the box intermediate the v the stoves, into the carbureter.

is protected withinthe lower cowling of the point'outside the fuselage, .nected with said conduit means pipes. The downtakes carry air from outheatingchamber and connected at one end w y inthe air directly to the engine.

front and rear ends of the same, forming ends of the same and valve mechanism for bridges between the stoves on the exhaust directing-intaken air toward one or the other I end of said box. s de and above the machine directly intothe 5. In apparatus of the character disclosed, intermediate portion of the box and the the combination of engine exhaust pipes havswing valve sends this air either directly up ing stoves thereon, a distributor box located into the carbureter or; indirectly, through between said stoves and having transverse conduits at opposite ends of the" same in con- The various parts of the device may all nection with said stoves, said box having a be made ofirelatively light sheet metal. The part at one end for connection with the air generally rectangular form of the air box intake of an engine carbureter,

the ends of the same and valve mechanism for directing intaken air toward one-or the other end of said box, said box having a vent machine and the transverse pipes 12, 14 exin the bottom of the same in linewith the tend through such cowling to the stoves on carburetor intake portion and a closure-for the exhaust, pipes outside the cowling. said vent yieldable to internal pressure in What is claimed is: the vent. 1 p 1 1. An air intake heater for aircraft, com- 6. In combination with an airplane fuseprising in combination with the fuselage and lage and engine having a carbureter intake, engine structures, an air heating chamber, a box connectedeat opposite ends with said air same to occupy a relatively small'space in between the two air'heaters. This air box per cowling of the fuselage and opening forwith the air intake for the engine, an air. air heater, conduit means connected with said intake extending from outsidethe upper porair intake and with said air heater, said con tion of the fuselage to an intermediate por duit means having-provision for connection tion of the box and valve means in said box of h same Wi h he earbllle er intake of the anair intakegives it the desired strength and enables the conduit opening into the box intermediate direction of airplane travel, an i an air intake, extending up through; the upfor forein the intaken air through the heat--eng1ne and means controllable to send theq ing chamb r to the engine or for sending such i taken air direetlg inte the ear eter i take, or indirectly t ough the air heater Into 2. In combination with the fuselage and the carbureter intake. engine structures of an airplane, conduit 7. In combinationwith an airplane fusemeans forming a chamber connected with lage andengine having a carbureter intake, the air intake of the engine, an air intake n air, opening into. said. conduit means from a per cowling of the fuse age and opemng foran air heater nwardly in the direction of airplane travel, an

mechanism in said conduit means ing the intaken air to the engine air intake or through the air heater to said engine air intake. Q

3. In combination with the fuselage. and taken air directly into the carburetor intake, engine structures ofv an airplane, conduit r indirec ly th g the ir h r'in e t means-forming a chamber connected with earb lretel intake, aid ndllifl n h v g the air intake of the engine, an air intake a vent opening through the cowling of the openinginto said conduit means from a fuselage and a pressure operable yieldable point outside the fuselage, an air heater con closure f r d Ven 1 4 *nected with said conduit means and valve 8. In combination, an air box having a and valve air heater gonduit means connected with saidof the same with the carbureter intake'of thev engine and means'controllable to send the mintake extendin up through the upneck portion for connection with a carbureter intake, said air box having means at opposits ends of the same for enabling connection with an air heater and having means intermediate its ends for enabling the connection of an air intake and a swing valve mounted in said air box opposite said air intake for directing intaken air toward one end or the other of the air box.

9. In combination, an air box having a neck portion for connection with a carbureter intake, said air box having means at opposite ends 'of the same for enabling connection with an air heater and having means intermediate its ends for enabling the connection of an air intake and a swing valve mounted in said air box opposite said air intake for directing intaken air toward one end or the other of the air box, said air box having a vent opposite the carbureter intake connection portion and a spring closed trap door for normally holding said vent closed.

In testimony whereof I aflix my signature.

LLOYD STEARMAN. 

